JP3893727B2 - Fuel injection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection valve for an internal combustion engine, and more particularly to prevention of erroneous determination during an airtight inspection of the fuel injection valve.
[0002]
[Prior art]
In an internal combustion engine, a fuel injection valve is connected to a fuel supply pipe that supplies fuel to the fuel injection valve by inserting a base end portion where a fuel intake port of the fuel injection valve is formed into an outlet end portion of the fuel supply pipe. Is called. An O-ring made of rubber or the like is tightly fitted on the outer periphery of the base end portion of the fuel injection valve so as to seal the peripheral surface of the base end portion of the fuel injection valve and the inner peripheral surface of the outlet end portion of the fuel supply pipe. It has become. The base end portion is generally formed with a stepped portion having a small diameter on the fuel inlet side, and is positioned by supporting an O-ring on the stepped surface.
[0003]
The quality of the seal by the O-ring is checked in an airtight inspection before the fuel injection valve is actually connected to the fuel supply pipe. For example, a fuel injection valve is connected to a cap-shaped inspection jig simulating the outlet end of a fuel supply pipe with an O-ring interposed, immersed in oil, and air or the like is fed into the inspection jig. It is determined by observing whether bubbles or the like are generated at the connection portion between the inspection jig and the inspection jig.
[0004]
[Problems to be solved by the invention]
By the way, at the time of the airtight inspection, a sealing failure between the O-ring and the inspection jig can be determined by the generation of bubbles or the like. However, even if the sealing performance between the O-ring and the peripheral surface of the base end portion is poor, bubbles are not generated if the sealing performance between the O-ring and the stepped surface is good. Therefore, even if the sealing performance between the O-ring and the peripheral surface of the base end portion is poor, bubbles are not generated if the sealing performance between the O-ring and the inspection jig and between the O-ring and the stepped surface is good. Therefore, it is determined that the fuel injection valve has good sealing performance.
[0005]
When the fuel injection valve thus determined is installed in a real vehicle, the O-ring vibrates along the peripheral surface of the base end portion of the fuel injection valve under the severe operating condition of the internal combustion engine, and between the step surface. If loosening occurs, complete sealing performance may not be ensured.
[0006]
The present invention has been made in view of the above circumstances, and provides a fuel injection valve capable of accurately determining whether or not a seal by an O-ring, particularly a sealing performance between a peripheral surface of a base end portion and an O-ring, is good in an airtight inspection. The purpose is to provide.
[0007]
[Means for Solving the Problems]
In the first aspect of the invention, the fuel injection valve is fitted with the base end portion where the fuel inlet is formed in the outlet end portion of the fuel supply pipe, and is kept airtight by an O-ring provided on the outer periphery of the base end portion. The O-ring positioning step is formed on the peripheral surface of the base end. In addition to such a configuration, the step surface of the step portion that supports the O-ring has a groove that is provided in a direction crossing the O-ring and that communicates the inside and the outside of the O-ring that is mounted in contact with the step surface .
[0008]
A gap is formed between the O-ring and the step surface by the groove in a direction crossing the O-ring. Even if the O-ring is in close contact with the step surface, this gap allows the inner side and the outer side sandwiching the contact portion to communicate with each other, so that the step surface is not sealed. Therefore, if the seal between the peripheral surface of the base end portion and the O-ring is poor, this can always be found during the airtight inspection.
[0009]
According to the second aspect of the present invention, by opening one end of the groove to the peripheral surface of the base end portion, the inner side and the outer side sandwiching the close contact portion with the step surface of the O ring no matter what the O ring deforms And communicate with each other.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows the entire side surface of the fuel injection valve of the internal combustion engine of the present invention, and FIG. 2 shows a cross section of the fuel injection valve along the line AA in FIG. The fuel injection valve basically has a configuration of a normal electromagnetic fuel injection valve. A fuel flow path 1c (see FIG. 2) is formed along the axis, and the fuel injection valve communicates with the injection hole 1a of the distal end portion 2. Yes. The base end portion 3 of the fuel injection valve 1 is a portion connected to the outlet end portion 7 of the fuel supply pipe indicated by the phantom line, and the base end portion 3 is provided with a supply port 1b serving as a fuel intake port. The fuel is sent to the flow path 1c. A connector portion 4 for power supply protrudes obliquely upward slightly below the base end portion 3.
[0011]
The base end portion 3 of the fuel injection valve 1 is formed with a step portion 31 having a small diameter portion 33 on the fuel supply port 1b side and a large diameter portion 34 on the distal end portion 2 side. On the outer periphery of the small diameter portion 33 of the base end portion 3, a sealing O-ring 5 and a ring 6 for preventing the separation are provided coaxially with the base end portion 3. The ring 5 is inserted into the small-diameter portion 33 and positioned by contacting the step surface 31a of the step portion 31. Then, the ring 6 is inserted into the annular groove (not shown) formed on the peripheral surface 33a of the small-diameter portion 33 and fitted into the base. Secure to the end 3.
[0012]
When the base end 3 of the fuel injection valve 1 is fitted into the outlet end 7 of the fuel supply pipe and the fuel injection valve 1 and the outlet end 7 of the fuel supply pipe are connected, the O-ring 6 It compresses to the radial direction of the valve 1, and closely_contact | adheres with the peripheral surface 33a of the small diameter part 33 of the base end part 3, and the internal peripheral surface 7a of the exit end part 7 of a fuel supply pipe, Between these peripheral surfaces 33a and 7a An annular contact surface portion is formed to maintain airtightness.
[0013]
The annular step surface 31a of the base end portion 3 is provided with a groove 32 in the width direction, and one end of the groove 32 reaches the outer periphery of the step surface 31 and opens to the peripheral surface 34a of the large diameter portion 34, The other end of the groove 32 reaches the inner periphery of the annular step surface 31a. Due to the groove 32, a gap S is formed between the O-ring 5 and the annular step surface 31a in a direction crossing the O-ring 5. By this gap S, a corner C formed by the annular step surface 31a, the peripheral surface 33a of the small diameter portion 33, and the O-ring 5, and an outer side sandwiching the annular contact surface portion of the O-ring 5 and the annular step surface 31a Has come to communicate.
[0014]
In addition, the cross-sectional shape of the groove | channel 32 can be made into arbitrary shapes, such as a rectangle and a triangle. The number of grooves 32 is one in the illustrated example, but a plurality of grooves may be provided.
[0015]
The airtight inspection of the fuel injection valve 1 will be described with reference to FIGS. FIG. 3 shows the base end 3 side at the time of an airtight inspection of the fuel injection valve 1. In order to perform an airtight inspection of the fuel injection valve 1, a cap-like shape simulating the outlet distal end portion 7 (FIG. 1) of the fuel supply pipe is formed at the base end portion of the fuel injection valve 1 as in the case of the conventional fuel injection valve. The inspection jig 8 (FIG. 3) is covered, air or the like is sent into the inspection jig 8, and the presence or absence of leakage of air or the like is confirmed. Leakage of air or the like flows out between the inspection jig 8 and the base end portion 3 of the fuel injection valve 1 as indicated by an arrow in FIG.
[0016]
When the seal on the peripheral surface 33a of the base end portion 3 is defective, air or the like sent into the inspection jig 8 passes through the defective seal portion and escapes to the corner C. In the case of a conventional fuel injection valve without a groove on the step surface, the air or the like that has escaped to the corner C may escape to the outside of the O-ring when the O-ring is pressed against the step surface and airtightness occurs. However, in the case of the fuel injection valve 1 of the present invention, the air leaked to the corner C passes through the gap S intersecting the O-ring 5. As a result, the outer surface of the O-ring 5 is pulled out, and a sealing failure on the peripheral surface 33a of the base end portion 3 can be reliably detected.
[0017]
When the seal on the inner peripheral surface 8a of the inspection jig 8 is defective, air or the like sent into the inspection jig 8 leaks to the outside of the O-ring 5 through the defective seal portion. This finds a seal failure.
[0018]
If neither the seal on the peripheral surface 33a of the base end 3 nor the seal on the inner peripheral surface 8a of the inspection jig 8 is defective, leakage of air or the like does not occur and the O-ring 5 has a good seal. Is known.
[0019]
As described above, according to the fuel injection valve of the present invention, regardless of whether or not the O-ring is in close contact with the positioning step surface and airtightness is generated, it is precisely on the peripheral surface of the small-diameter portion of the base end portion. The quality of the seal can be determined.
[0020]
Note that one end of the groove opens to the peripheral surface of the large-diameter portion of the base end portion to ensure communication between the corner and the outside, but the end position of the groove is sufficiently close to the outer peripheral edge of the annular step surface As long as communication between the corner and the outside is ensured, there is no limitation.
[Brief description of the drawings]
FIG. 1 is a side view of a fuel injection valve according to the present invention.
2 is a cross-sectional view of the fuel injection valve taken along line AA in FIG.
FIG. 3 is a partial cross-sectional side view of the fuel injection valve of the present invention and an airtightness inspection jig connected to the fuel injection valve.
[Explanation of symbols]
1 Fuel Injection Valve 1b Fuel Supply Port (Fuel Intake Port)
2 distal end portion 3 base end portion 31 step portion 31a step surface 32 groove 33 small diameter portion 33a peripheral surface 34 large diameter portion 34a peripheral surface 5 O-ring 7 outlet end portion 8 of fuel supply pipe inspection jig

Claims (2)

A fuel in which a base end portion in which a fuel inlet is formed is fitted into an outlet end portion of a fuel supply pipe, and an air tightness between the base end portion and the outlet end portion is maintained by an O-ring provided on the outer periphery of the base end portion. In a fuel injection valve, wherein a step for positioning an O-ring is formed on the peripheral surface of the base end portion, the step surface of the step that supports the O-ring crosses the O-ring in a direction. A fuel injection valve comprising a groove that is provided and communicates with an inside and an outside of an O-ring that is mounted in contact with the step surface .   2. The fuel injection valve according to claim 1, wherein one end of the groove is opened on the peripheral surface of the base end portion.

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